Upgrading rails version

From Rails 3.1 to 3.2

Deprecation warnings while testing locally

rspec stub! is deprecated

rspec mock is deprecated - use double

Deprecation warnings while deploying to Heroku

https://gist.github.com/mtc2013/6079095

From 3.2 to 4.0

Heroku will hopefully deal automatically with the deprecation warnings

(http://stackoverflow.com/a/9042604)

(https://devcenter.heroku.com/articles/rails4#upgrading-a-rails3-app)